* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background: #f5f7fa;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    color: #333;
    line-height: 1.6;
}

/* 导航栏样式 */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: linear-gradient(135deg, #2c3e50, #1a2530);
    color: white;
    padding: 15px 50px;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 15px rgba(0, 0, 0, 0.2);
}

.logo-container {
    display: flex;
    align-items: center;
    gap: 15px;
}

.logo-container img {
    height: 45px;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.3));
}

.logo-container h1 {
    font-size: 1.8rem;
    font-weight: 600;
    color: white;
}

.nav-links {
    display: flex;
    gap: 30px;
    list-style: none;
}

.nav-links a {
    color: rgba(255, 255, 255, 0.85);
    text-decoration: none;
    font-weight: 500;
    font-size: 1.1rem;
    transition: all 0.3s ease;
    padding: 8px 12px;
    border-radius: 5px;
}

.nav-links a:hover {
    color: white;
    background: rgba(255, 255, 255, 0.1);
}

.nav-links a.active {
    color: #3498db;
    background: rgba(255, 255, 255, 0.15);
}

.auth-buttons {
    display: flex;
    gap: 15px;
}

.login-btn,
.register-btn {
    padding: 10px 25px;
    border-radius: 30px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
    font-size: 1rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.login-btn {
    background: rgba(255, 255, 255, 0.15);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.login-btn:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: translateY(-2px);
}

.register-btn {
    background: #3498db;
    color: white;
}

.register-btn:hover {
    background: #2980b9;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(52, 152, 219, 0.3);
}

/* 英雄区域 */
.hero {
    background: linear-gradient(rgba(44, 62, 80, 0.9), rgba(26, 37, 48, 0.9)),
        url('../img/hero-bg.avif');
    background-size: cover;
    background-position: center;
    color: white;
    text-align: center;
    padding: 120px 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.hero h2 {
    font-size: 3.5rem;
    margin-bottom: 20px;
    max-width: 800px;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.hero p {
    font-size: 1.4rem;
    max-width: 700px;
    margin-bottom: 40px;
    opacity: 0.9;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    margin-top: 20px;
}

.btn {
    padding: 15px 35px;
    border-radius: 30px;
    font-weight: 500;
    font-size: 1.1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
    display: flex;
    align-items: center;
    gap: 10px;
}

.btn-primary {
    background: #3498db;
    color: white;
}

.btn-primary:hover {
    background: #2980b9;
    transform: translateY(-3px);
    box-shadow: 0 6px 15px rgba(52, 152, 219, 0.4);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.15);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: translateY(-3px);
}

/* 实验展示区 */
.section {
    padding: 80px 50px;
}

.section-title {
    text-align: center;
    margin-bottom: 60px;
}

.section-title h2 {
    font-size: 2.5rem;
    color: #2c3e50;
    margin-bottom: 15px;
}

.section-title p {
    font-size: 1.2rem;
    color: #555;
    max-width: 700px;
    margin: 0 auto;
}

.experiments-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
    max-width: 1400px;
    margin: 0 auto;
}

.experiment-card {
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    height: 100%;
}

.experiment-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 12px 25px rgba(0, 0, 0, 0.15);
}

.card-image {
    height: 200px;
    overflow: hidden;
}

.card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.experiment-card:hover .card-image img {
    transform: scale(1.05);
}

.card-content {
    padding: 25px;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.card-content h3 {
    font-size: 1.5rem;
    color: #2c3e50;
    margin-bottom: 15px;
}

.card-content p {
    color: #555;
    margin-bottom: 20px;
    flex-grow: 1;
}

.card-meta {
    display: flex;
    justify-content: space-between;
    color: #777;
    font-size: 0.9rem;
    margin-top: 10px;
}

.card-meta span {
    display: flex;
    align-items: center;
    gap: 5px;
}

.tag {
    display: inline-block;
    padding: 5px 12px;
    background: #e1f0ff;
    color: #2980b9;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
    margin-top: 15px;
}

/* 实验详情区 */
.experiment-detail {
    max-width: 1200px;
    margin: 0 auto;
    background: white;
    border-radius: 15px;
    box-shadow: 0 5px 25px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    display: none;
}

.detail-header {
    padding: 30px;
    background: #f8f9fa;
    border-bottom: 1px solid #eaeaea;
}

.detail-header h2 {
    font-size: 2rem;
    color: #2c3e50;
    margin-bottom: 10px;
}

.detail-header p {
    color: #777;
    max-width: 800px;
}

.detail-content {
    padding: 30px;
    display: flex;
    flex-wrap: wrap;
    gap: 30px;
}

.detail-main {
    flex: 1;
    min-width: 300px;
}

.detail-main h3 {
    font-size: 1.5rem;
    color: #2c3e50;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 1px solid #eaeaea;
}

.detail-main p {
    margin-bottom: 20px;
    line-height: 1.8;
}

.detail-sidebar {
    width: 350px;
}

.resources-card {
    background: #f8f9fa;
    border-radius: 12px;
    padding: 25px;
    margin-bottom: 30px;
}

.resources-card h3 {
    font-size: 1.4rem;
    color: #2c3e50;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.resource-list {
    list-style: none;
}

.resource-list li {
    padding: 15px 0;
    border-bottom: 1px solid #eaeaea;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.resource-list li:last-child {
    border-bottom: none;
}

.resource-name {
    display: flex;
    align-items: center;
    gap: 10px;
}

.download-btn {
    background: #3498db;
    color: white;
    border: none;
    padding: 8px 15px;
    border-radius: 20px;
    cursor: pointer;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 6px;
    transition: all 0.3s ease;
}

.download-btn:hover {
    background: #2980b9;
}

.video-container {
    margin-top: 30px;
}

.video-placeholder {
    background: #eaeaea;
    border-radius: 12px;
    height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #777;
    font-weight: 500;
    margin-top: 15px;
}

/* 特色功能区域 */
.features {
    background: #f8f9fa;
}

.features-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    max-width: 1200px;
    margin: 0 auto;
}

.feature-card {
    background: white;
    border-radius: 15px;
    padding: 35px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    text-align: center;
    transition: all 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 12px 25px rgba(0, 0, 0, 0.1);
}

.feature-icon {
    width: 80px;
    height: 80px;
    background: #e1f0ff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 25px;
    font-size: 2rem;
    color: #3498db;
}

.feature-card h3 {
    font-size: 1.5rem;
    color: #2c3e50;
    margin-bottom: 15px;
}

.feature-card p {
    color: #555;
}

/* 页脚 */
.footer {
    background: #2c3e50;
    color: white;
    padding: 60px 50px 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    max-width: 1200px;
    margin: 0 auto 40px;
}

.footer-column h3 {
    font-size: 1.4rem;
    margin-bottom: 25px;
    position: relative;
    padding-bottom: 10px;
}

.footer-column h3::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 50px;
    height: 3px;
    background: #3498db;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 15px;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 10px;
}

.footer-links a:hover {
    color: white;
    transform: translateX(5px);
}

.copyright {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.9rem;
    max-width: 1200px;
    margin: 0 auto;
}

/* 关闭按钮 */
.close-detail {
    position: absolute;
    top: 20px;
    right: 20px;
    background: #e74c3c;
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 1.2rem;
    transition: all 0.3s ease;
}

.close-detail:hover {
    transform: rotate(90deg);
    background: #c0392b;
}

/* 课程导航 */
.course-nav {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.course-btn {
    padding: 10px 25px;
    border-radius: 30px;
    background: white;
    color: #2c3e50;
    border: 1px solid #e0e0e0;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
}

.course-btn:hover,
.course-btn.active {
    background: #3498db;
    color: white;
    border-color: #3498db;
}

/* 教学资源区 */
.resource-category {
    background: white;
    border-radius: 15px;
    padding: 30px;
    margin-bottom: 40px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
}

.resource-category h3 {
    font-size: 1.8rem;
    color: #2c3e50;
    margin-bottom: 25px;
    display: flex;
    align-items: center;
    gap: 12px;
    padding-bottom: 15px;
    border-bottom: 2px solid #eaeaea;
}

.resource-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
}

.resource-item {
    display: flex;
    gap: 15px;
    padding: 20px;
    background: #f9fafb;
    border-radius: 12px;
    transition: all 0.3s ease;
}

.resource-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.resource-icon {
    width: 60px;
    height: 60px;
    background: #e1f0ff;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: #3498db;
    flex-shrink: 0;
}

.resource-content h4 {
    font-size: 1.2rem;
    color: #2c3e50;
    margin-bottom: 8px;
}

.resource-content p {
    color: #666;
    font-size: 0.95rem;
}

/* 关于我们区域 */
.about-container {
    max-width: 1200px;
    margin: 0 auto;
}

.about-section {
    background: white;
    border-radius: 15px;
    padding: 40px;
    margin-bottom: 40px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
}

.about-section h3 {
    font-size: 1.8rem;
    color: #2c3e50;
    margin-bottom: 25px;
    display: flex;
    align-items: center;
    gap: 12px;
    padding-bottom: 15px;
    border-bottom: 2px solid #eaeaea;
}

.about-section p {
    color: #555;
    line-height: 1.8;
    margin-bottom: 25px;
}

.teacher-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 25px;
    margin-top: 20px;
}

.teacher-card {
    background: #f9fafb;
    border-radius: 12px;
    padding: 25px;
    text-align: center;
    transition: all 0.3s ease;
}

.teacher-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.teacher-avatar {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    object-fit: cover;
    margin: 0 auto 20px;
    border: 3px solid #eaeaea;
}

.teacher-card h4 {
    font-size: 1.3rem;
    color: #2c3e50;
    margin-bottom: 8px;
}

.teacher-card .position {
    color: #3498db;
    font-weight: 500;
    margin-bottom: 10px;
}

.teacher-card .research {
    color: #666;
    font-size: 0.9rem;
}


/* 帮助中心样式 */
.help-center {
    background: white;
    border-radius: 15px;
    padding: 40px;
    margin: 40px 0;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
}

.help-center h3 {
    font-size: 1.8rem;
    color: #2c3e50;
    margin-bottom: 25px;
    display: flex;
    align-items: center;
    gap: 12px;
    padding-bottom: 15px;
    border-bottom: 2px solid #eaeaea;
}

.help-categories {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 30px;
}

.help-category {
    background: #f9fafb;
    border-radius: 15px;
    padding: 25px;
    transition: all 0.3s ease;
}

.help-category:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
}

.help-category h4 {
    font-size: 1.4rem;
    color: #2c3e50;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.help-category h4 i {
    color: #3498db;
    font-size: 1.5rem;
}

.help-questions {
    list-style: none;
}

.help-questions li {
    padding: 12px 0;
    border-bottom: 1px solid #eaeaea;
    display: flex;
    align-items: center;
    gap: 10px;
}

.help-questions li:last-child {
    border-bottom: none;
}

.help-questions li i {
    color: #27ae60;
    min-width: 20px;
}

.help-questions li a {
    color: #555;
    text-decoration: none;
    transition: all 0.3s ease;
}

.help-questions li a:hover {
    color: #3498db;
    transform: translateX(5px);
}

/* 添加状态消息样式 */
.status-message {
    animation: slideIn 0.3s ease-out, fadeOut 0.3s ease-out 2.7s;
}

@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }

    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@keyframes fadeOut {
    from {
        opacity: 1;
    }

    to {
        opacity: 0;
    }
}

/* 新增动画效果 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animated {
    animation: fadeIn 0.5s ease-out;
}

/* 响应式设计 */
@media (max-width: 992px) {
    .navbar {
        padding: 15px 30px;
    }

    .nav-links {
        display: none;
    }

    .section {
        padding: 60px 30px;
    }

    .hero h2 {
        font-size: 2.8rem;
    }

    .hero p {
        font-size: 1.2rem;
    }
}

@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        gap: 20px;
        padding: 20px;
    }

    .auth-buttons {
        width: 100%;
        justify-content: center;
    }

    .hero {
        padding: 80px 20px;
    }

    .hero h2 {
        font-size: 2.2rem;
    }

    .hero p {
        font-size: 1.1rem;
    }

    .hero-buttons {
        flex-direction: column;
        gap: 15px;
        width: 100%;
        max-width: 300px;
    }

    .btn {
        width: 100%;
        justify-content: center;
    }

    .detail-content {
        flex-direction: column;
    }

    .detail-sidebar {
        width: 100%;
    }
}

@media (max-width: 480px) {
    .section {
        padding: 50px 20px;
    }

    .section-title h2 {
        font-size: 2rem;
    }

    .experiments-container {
        grid-template-columns: 1fr;
    }
}